The National Cancer Institute estimates that 23,380 adults (12,820 men and 10,560 women) will be diagnosed with brain and other nervous system tumors in 2014 in the United States alone. Glioblastoma is a particularly aggressive and invasive form of brain cancer, and the median survival ranges from 31.9 months for patients 20-29 years of age to only 5.6 months in patients 80 years and older. (D. R. Johnson and B. P. O'Neill, “Glioblastoma survival in the United States before and during the temozolomide era”, J. Neurooncol. 2012, 107:359-64). One method for improving median survival in glioblastoma patients is to increase the completeness of tumor tissue resected during surgery, while not increasing the amount of healthy brain tissue removed. (W. Stummer et al., “Extent of resection and survival in glioblastoma multiforme: identification of and adjustment for bias”, Neurosurgery 2008, 62:564-76; B. Chen et al., “Gross total resection of glioma with the intraoperative fluorescence-guidance of fluorescein sodium”, Int. J. Med. Sci. 2012, 9:708-14). In clinical practice however, the distinction between malignant growth and healthy brain tissue can be difficult to make, and the resection of healthy brain increases the incidence of post-surgical morbidity.
Targeted radiation therapy is seen as an efficient technique of selectively ablating malignant growth while sparing surrounding tissues. These efforts, however, are often stricken by failure to deliver sufficiently high concentrations of therapeutic nuclides to cancer cells while keeping the radiation dose to excretory organs and bone marrow within safe limits.